This invention relates to neutron detection.
A neutron-sensitive microchannel plate (MCP) can be used to detect special nuclear materials (SNM), such as plutonium, or can be used in neutron imaging. A microchannel plate can be formed by bonding a glass plate between an input electrode and an output electrode, and providing a high voltage direct current (DC) field between the electrodes. The glass plate is perforated with a substantially regular, parallel array of microscopic channels, e.g., cylindrical and hollow channels. Each channel, which can serve as an independent electron multiplier, has an inner wall surface formed of a semi-conductive and electron emissive layer.
A gamma ray, atomic particle, or subatomic particle, e.g., neutron, alpha or beta particle, upon impacting the microchannel plate surface or penetrating into the bulk, will ultimately generate secondary electrons. Regardless of the type and source of the impinging particle, the resulting secondary electrons accelerate along the channel in the DC electric field between the high voltage electrodes. The secondary electrons themselves collide with the channel wall to create a cascade of additional secondary electrons that is registered as an electrical signal at the end of the channel. A microchannel plate detector will register an electrical signal for either a neutron or a gamma ray incident on the detector from the external environment, with a certain level of efficiency depending on the material composition.